The hydraulic system (blood-side fluid system) of a blood treatment device, for example a dialysis machine, has to be filled with fluid, for example an NaCl solution or another sterile physiological solution, before being connected up to a patient, in such a way that air pockets in the system that would be dangerous for a patient connected up to the fluids of the system are eliminated. Furthermore, the hydraulic system should be flushed with the filled-in fluid for a certain period of time in order to filter/wash out any contaminants, dirt particles, etc. that may have deposited in the system before the system is connected up to the patient. On an extracorporeal blood treatment device, these two procedures are performed in the scope of a filling —circulation cycle, which is again an object of the invention in hand.
In the state of the art, there are fluid containers preferably in the shape of plastic bags designed especially for extracorporeal blood treatment devices of this relevant type in order to enable, among others, the device functions as described above. These kind of fluid containers are also manufactured and sold by the applicant.
As a rule, such a fluid container has a fluid intake chamber and two, preferably closable, fluid connectors. On a first of the two connectors, an arterial line section, and on the second connector, a venous line section of the hydraulic system (fluid system or also referred to as fluid conducting system) of the extracorporeal blood treatment device can be connected. The fluid bag as well as the two line sections together constitute a circulation device of the extracorporeal blood treatment device.
For the fluid system filling process, first the arterial line section is connected to the first fluid connector of the bag, and after opening of the first fluid connector, the hydraulic system is filled. The venous line section of the system first remains open to the atmosphere or is connected to a drain, a container or a bag so that air inside the system can escape and be vented in the atmosphere. As soon as the filling process is completed, the venous line section is connected to the second fluid connector of the bag by way of reconnecting in order to circulate the fluid inside the hydraulic system of the extracorporeal blood treatment device for a certain period of time or a certain volume of flow through the bag chamber.
During this optional circulation process, the fluid flows through internal filtering devices of the system in which remaining air pockets are removed/filtered out with the fluid. If necessary, the venous line section of the hydraulic system can again be disconnected from the second fluid connector of the fluid bag and the fluid inside the hydraulic system can be flushed out again under constant supply of fluid from the container. As a rule, however, the arterial line section is disconnected from the fluid bag and connected to the patient so that the fluid contained in the blood hose system can be displaced and discharged by the blood. Then the venous line section can be connected up to the patient. Upon completion of the circulation process and the application of both line sections (venous and arterial) to the patient for treatment, the filling/circulation cycle preparing for patient treatment is completed.
The description above of the filling/circulation cycle of a hydraulic system/fluid conducting system of an extracorporeal blood treatment device (dialysis machine) known from the state of the art indicates that the fluid bag remains in the system circuit for the filling and circulation processes, i.e. that the fluid inside the system is circulated through the fluid bag and/or its fluid chamber. As a result, the fluid in the fluid bag may get contaminated. As a consequence, the fluid bag has to be replaced by a new fluid bag in each case and cannot be used for a later therapy phase, e.g. during re-infusion. As a result, the fluid bag for the filling/circulation cycle performed before is disposed of independently of its residual fill plane. It is obvious that this procedure results in the wasting of a large quantity of fluid in case of a high patient treatment number because the fluid content of a fluid bag can only be used (incompletely) for the filling/circulation cycle.
Furthermore, fluid bags with two connectors as custom-made products are more expensive than conventional fluid bags, for example NaCl bags/bottles, with only a single connector. For this reason, the filling and recirculation device described above does not only imply a waste of filling and flushing fluid, but also an increase in cost due to expensive disposable fluid bags.
Finally, the conduits of the extracorporeal fluid conducting system of the blood treatment device that have to be filled permanently have to be reconnected for the individual filling and recirculation steps. In other words, the arterial line first has to be coupled with the fluid container, and the venous line has to be disconnected so that the flushing procedure can be carried out. Then the venous line has to be coupled with the fluid container again so that recirculation can be performed. For the final further flushing process, the venous line is disconnected again. When, finally, the arterial line and the venous line are applied to the patient, both fluid connectors on the fluid container have to be closed to avoid uncontrolled draining of the fluid container. This indicates that the handling of the known filling and recirculation system is not especially user-friendly.